Power manager and power managing method for battery-powered application

• US 20070029975A1
• Filed: 07/19/2005
• Published: 02/08/2007
• Est. Priority Date: 07/19/2005
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Linear Technology Corporation (Analog Devices, Inc.)
• Inventors: Barcelo, Trevor, Nork, Samuel, Martin, Steven, Simmons, David, Zemke, Roger
• Granted Patent: US 7,710,079 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A power manager is configured to manage power for a battery-powered application. A power source, a load and a battery are interconnected through a circuit path. Power from the power source is provided to the load and battery by a switching regulator. Various implementations are presented.

Claims

1. A power manager for managing power for a battery-powered application, comprising:

a circuit path for interconnecting a power source, a load and a battery; and

a switching regulator for providing power from the power source to the load and battery through the circuit path.

2. The power manager according to claim 1, further comprising

a first circuit configured for coupling the battery to the circuit path to charge the battery;

and

a second circuit configured for monitoring a voltage across the first circuit, and in response controlling the switching regulator to limit the voltage within a voltage limit.

3. The power manager according to claim 2, wherein

the voltage limit varies depending on battery current.

4. The power manager according to claim 2, wherein

the first circuit comprises at least one resistance element.

5. The power manager according to claim 1, further comprising

a third circuit configured for monitoring current in the circuit path, and in response controlling the switching regulator to limit the current within a current limit.

6. The power manager according to claim 5, wherein

the third circuit is further configured to obtain an average current in the circuit path so as to compare the average current with the current limit.

7. The power manager according to claim 5, wherein

the third circuit is configured to limit the current in the circuit path when the current exceeds the current limit, causing a voltage in the circuit path to drop, and when the voltage in the circuit path drops to near a battery voltage, the first circuit becomes resistive and the load is prioritized to receive the current.

8. The power manager according to claim 6, wherein

the third circuit is configured to limit the current in the circuit path when the average current exceeds the current limit, causing a voltage in the circuit path to drop, and when the voltage in the circuit path drops to near a battery voltage, the first circuit is unable to deliver programmed charge current to the battery.

9. The power manager according to claim 8, wherein

the first circuit is configured to provide current from the battery to the load when the voltage in the circuit path drops below the battery voltage.

10. The power manager according to claim 9, wherein

the first circuit includes, or is configured to operate as, a diode to provide the current from the battery to the load.

11. A power manager for managing power for a battery-powered application, comprising:

a circuit path for interconnecting a power source and a load to provide power from the power source to the load;

a first circuit, comprising at least one resistance element, configured for coupling a battery to the circuit path to charge the battery; and

a second circuit configured for monitoring an output voltage in the circuit path, and in response, limiting the output voltage within a battery voltage plus an offset voltage.

12. The power manager according to claim 11, wherein

the offset voltage is of a magnitude selected based on a battery current magnitude.

13. The power manager according to claim 11, wherein

the second circuit is further configured to compare the output voltage with a reference voltage when the battery voltage is lower than the reference voltage, and in response, limiting the output voltage within the reference voltage.

14. A power manager for managing power for a battery-powered application, comprising:

a circuit path for interconnecting a power source and a load to provide power from the power source to the load;

a first circuit, comprising at least one resistance element, configured for coupling a battery to the circuit path to charge the battery; and

a second circuit configured for monitoring current in the circuit path, and in response limiting the current within a current limit, wherein

the second circuit limits the current when the current exceeds the current limit, causing a voltage in the circuit path to drop, and when the voltage in the circuit path drops to near a battery voltage, the first circuit is unable to deliver programmed charge current to the battery.

15. The power manager according to claim 14, wherein

the first circuit provides current from the battery to the load when the voltage in the circuit path drops below the battery voltage.

16. The power manager according to claim 15, wherein

the first circuit includes, or is configured to operate as, a diode to provide the current from the battery to the load.

17. A power manager for managing power for a battery-powered application, comprising:

a circuit path for interconnecting a power source and a load;

a first circuit configured for coupling a battery to the circuit path to charge the battery;

a controller configured for controlling power delivery through the circuit path to the load and battery,

a second circuit configured for monitoring a voltage across the first circuit to detect whether the voltage exceeds a voltage limit; and

a third circuit configured for monitoring current in the circuit path to detect whether the current exceeds a current limit,

wherein the controller limits the power delivery in response to any one of the second circuit'"'"'s detection and the third circuit'"'"'s detection.

18. The power manager according to claim 17, wherein

the voltage limit varies depending on battery current.

19. The power manager according to claim 17, wherein

the first circuit comprises at least one resistance element.

20. The power manger according to claim 17, wherein

the controller comprises:

a switching regulator for delivering power to the load and battery according to a switching pulse; and

a switching controller configured for terminating the switching pulse during a regulator switching cycle to establish a regulator duty cycle based upon a detection by the second or third circuit.

21. The power manager according to claim 20, wherein

the second circuit is configured to obtain an average voltage across the first circuit so as to compare the average voltage with the voltage limit, and

the third circuit is configured to obtain an average current in the circuit path so as to compare the average current with the current limit.

22. The power manager according to claim 17, wherein

the third circuit is configured to limit the current in the circuit path when the current exceeds the current limit, causing a voltage in the circuit path to drop, and when the voltage in the circuit path drops to near a battery voltage, the first circuit becomes resistive and the load is prioritized to receive the current.

23. The power manager according to claim 17, wherein

the controller limits the power delivery when the current in the circuit path exceeds the current limit, causing a voltage in the circuit path to drop, and when the voltage drops to near a battery voltage, the first circuit is unable to deliver programmed charge current to the battery.

24. The power manager according to claim 23, wherein

the first circuit provides current from the battery to the load when the voltage in the circuit path drops below the battery voltage.

25. The power manager according to claim 24, wherein

the first circuit includes, or is configured to operate as, a diode to provide the current from the battery to the load.

26. A power managing method for a battery-powered application, comprising the steps of:

interconnecting a power source and a load through a circuit path to provide power from the power source to the load;

coupling a battery to the circuit path through a battery charger for charging the battery;

controlling power delivery through the circuit path to the load and battery,

monitoring a voltage across the battery charger to detect whether the voltage exceeds a voltage limit;

monitoring current in the circuit path to detect whether the current exceeds a current limit, and

limiting the power delivery in response to detection of the voltage exceeding the voltage limit or detection of the current exceeding the current limit.